    with the `:divElem`, `:moduleCode`, `:lessonType`, `:lessonGroup` keys."
   [moduleCode lessonType lessonLabel bgColorCssClass isActuallySelected?
    & {:keys [ModulesMap]
-      :or   {ModulesMap (aget js/window "ModulesMap")}}]
+      :or   {ModulesMap (get-ModulesMap)}}]
   (let [moduleName          (get-in ModulesMap [moduleCode "name"])
         modulesMapLessonSeq (get-in ModulesMap [moduleCode "lessons" lessonType
                                                 lessonLabel])]

   NOTE: This function should only be called by
         `add-module-lesson-groups-from-url-hash!`"
  [moduleInfoSeq]
  (let [ModulesMap         (aget js/window "ModulesMap")

        moduleLessonGroupsMap
        (reduce (fn [lgMap modInfo]

  (fn [evt ui]
    (.addClass (aget ui "helper") "lesson-draggable-helper")
    (.css (aget ui "helper") "cursor" "grabbing")
    (let [ModulesMap         (get-ModulesMap)
          ; Get all lesson groups
          allLessonGroupsMap (get-in ModulesMap [moduleCode "lessons"
                                                 lessonType])
